I purchased two tiny plants of this penstemon from the Denver Botanic Garden last spring. (Thanks to Mike Kintgen for collecting the seed and Michael Bone for growing it!) I stuck them in the ground in what is essentially western clay and they have grown and flowered beautifully! They are still flowering now on October 3 which is nearly time for our first freeze. If they continue to grow, I will have plenty of seed.
P. fasciculatus resembles P. pinifolius superficially and from a distance, but the size, foliage and flowers are different. I've attached two photos taken with my cell phone to give people an idea of what it looks like.
Very nice, I like it, it does indeed look like P. pinifolius, sort of like pinifolius crossed with the slightly down curved tubes of Penstemon eatonii... the best of both. I hope that it proves hardy for you, it does grow at fairly high elevation in Mexico. Barbara, nice to have the visual follow-up showing this great looking species, glad you had some success.
Maybe Panayoti can tells us regarding hardiness.
To follow more about this rare Mexicon penstemon species, follow this link:
http://nargs.org/smf/index.php?topic=294.0